Attributing intentions to random motion engages the posterior superior temporal sulcus

Abstract

The right posterior superior temporal sulcus (pSTS) is a neural region involved in assessing the goals and intentions underlying the motion of socialagents. Recent research has identified visual cues, such as chasing, that trigger animacy detection and intention attribution. When readily available in avisual display, these cues reliably activate the pSTS. Here, using functional magnetic resonance imaging, we examined if attributing intentions torandom motion would likewise engage the pSTS. Participants viewed displays of four moving circles and were instructed to search for chasing ormirror-correlated motion. On chasing trials, one circle chased another circle, invoking the percept of an intentional agent; while on correlated motiontrials, one circle's motion was mirror reflected by another. On the remaining trials, all circles moved randomly. As expected, pSTS activation was greaterwhen participants searched for chasing vs correlated motion when these cues were present in the displays. Of critical importance, pSTS activation wasalso greater when participants searched for chasing compared to mirror-correlated motion when the displays in both search conditions were statisticallyidentical random motion. We conclude that pSTS activity associated with intention attribution can be invoked by top-down processes in the absence ofreliable visual cues for intentionality. © The Author (2012). Published by Oxford University Press.